Polyurethane Gaskets

Polyurethane Foam Gasket Not a Seal

Polyurethane, sometimes referred to just as ‘urethane’ is one of the most widely used materials for seals and gaskets. It’s inexpensive and has characteristics that make it very useful. Just be careful not to use urethane gasketing foam when you need a polyurethane seal!  A polyurethane foam gasket is different from a polyurethan seal.

Polyurethane properties

Polyurethane is formed by reacting isocyanate with polyol. Isocyanate is a simple compound of nitrogen oxygen and carbon while polyols are formed from oxygen, hydrogen and carbon. Put them together and you get materials that make excellent seals and gaskets.

Polyurethane seals work well from around -65°F up to 210°F. Below this minimum they become brittle while at higher temperatures they melt. Polyurethane is tough with good impact resistance and load bearing capacity. It’s also resistant to attack by petroleum and hydraulic oils.

Polyurethane is produced in a range of hardnesses, although the bulk of the material used for seals is around 95 Shore A. It’s tough, stronger than natural rubber, and abrasion resistant.

Polyurethane becomes a lot softer when foamed. This entails adding a foaming agent to the isocyanate/polyol reaction to create a gas. As the liquid solidifies this leaves bubbles dispersed throughout the material, which gives it a springy resilience.

Applications for polyurethane foam

Cushioning is probably the biggest application. Polyurethane foam is used in furniture, shoes and anywhere else that compliance and recovery are sought after. Gasketing is another common use. Here it’s compressibility cushions against impacts and takes up manufacturing tolerances.

One time not to use polyurethane foam is when sealing is needed. Most polyurethane foams have an open cell structure, so fluids can pass through.

Polyurethane seal applications

With it’s excellent abrasion resistance, polyurethane is often used in situations where there’s relative movement. Seals around rods in hydraulic cylinders is one example, where the oil resistance also helps ensure long life. Pipe seals are another common application, as are wipers and shaft seals.

Buy the right polyurethane!

Polyurethane, or just plain urethane, is a good choice for many seal and gasket applications. Just remember that in it’s foamed state it may not provide much of a seal!

Properties of Neoprene Gasket Material

Neoprene, which is also known as “polychloroprene,” is a type of synthetic rubber produced by the polymerization of chloroprene. Neoprene gasket material has become very common due to the fact that it resists the likes of ozone, sunlight, oxidation and many petroleum derivatives. Additionally, neoprene is characterized as being weather-, combustion-, water- and chemical-resistant. As you can see, it’s popular because it is resistant to many types of damages. What’s more, it’s also resistant to damage from twisting and flexing.

Here’s a closer look at the properties of neoprene so you can judge whether or not it’s a good material for your application:

  • Stretch and cushioning properties: Neoprene is elastic and form-fitting, able to conform to various sizes and shapes. It’s also cushioning, able to absorb shock.
  • Various grades available: From cloth inserted neoprene, which is reinforced with nylon for additional stability, to flame retardant neoprene, which passes a variety of flammability specifications, there are several grades available to suit any application. Other popular grades include commercial, FDA approved, diaphragm and high tensile strength.
  • General gauge thicknesses vary in size from 3/32-inch up to 2 inches.
  • Hardness ratings vary from 40 to 80.
  • Plate finish.
  • Neoprene can withstand temperatures ranging from -20 degrees F to 180 degrees F.
  • Tensile strength ranges from 900 to 1,000 PSI.
  • Elongation ranges from 350% to 400%.
  • Finally, widths are 36 inches, 48 inches or 72 inches.
  • Pressure sensitive adhesive, or PSA, are available upon request.
  • We fabricate neoprene gaskets through proven manufacturing processes that include waterjet cutting, flash cutting and die cutting.

One other neat feature about neoprene is that it’s impermeable, meaning that it can work as a tight barrier to prevent the escaping of gases or liquids.

For more information on the neoprene material and neoprene gaskets, and to speak with someone about placing an order, contact us today.